Childhood acute lymphoblastic leukemia: Four years evaluation of protocols 2013 and 2016 in a single center in Indonesia, a lower-middle-income country

BACKGROUND

The prognosis of childhood acute lymphoblastic leukemia (ALL) in Indonesia, a lower-middle-income country (LMIC), is lower than in high income countries (HICs). The Indonesian ALL2013 protocol resulted in too many toxic deaths (21%) and abandonments (11%). Therefore, we drafted an adapted protocol, ALL2016. Main changes: no anthracyclines in standard risk (SR), prednisone replaced dexamethasone at induction in high risk (HR), and anthracyclines and cyclophosphamide were rescheduled in HR.

PROCEDURE

Patients (aged: 1-18 years) were stratified into SR and HR. HR was defined as age over 10 years, leucocyte count over 50 × 10⁹ /L, central nervous system (CNS) involvement, mediastinal mass, T-cell phenotype, testicular involvement, or poor prednisone response.

RESULTS

ALL2013 included 174 patients (106 SR and 68 HR) and ALL2016 188 (91 SR and 97 HR). Although the number of HR patients was significantly higher in ALL2016 (51.6% vs. 39.1%; p = .017), the outcome of ALL2016 improved over ALL2013 (4-year-probable overall survival (pOS) 60.1% vs. 50.0%; p = .042 and 4-year-probable event-free survival (pEFS) 49.5% vs. 36.8%; p = .018). ALL2016 showed a nonsignificant advantage for SR patients (4-year-pEFS 56.0% vs. 47.2%; p = .220 and 4-year-pOS 70.3% vs. 61.3%; p = .166), but less toxic deaths (7% vs. 20%; p = .011). In HR group, the outcomes were significantly better in ALL2016 (4-year-pEFS 43.3% vs. 20.6%; p = .004; 4-year-pOS 50.5% vs. 32.4%; p = .014) especially due to less relapses (31% vs. 62%; p = .001). Isolated CNS relapses went down from 18 to 8% in HR (p = .010) and 11 to 5% in SR (p = .474). Both SR and HR showed lower numbers of abandonment in ALL2016 (6% vs. 14%; p = .039).

CONCLUSIONS

Overall ALL2016 results improved over ALL2013. Modest changes in protocol resulted in less initial toxicity and abandonments.

Directional Converter Arm Method for Surface and Interfacial Tension Measurements with a Top-Loading Balance

A method is described for utilizing a top-loading balance, with a directional converter arm, in vertical-pull surface force measurements. The Padday rod-pull technique, the du Noüy ring method, and the Wilhelmy plate method are utilized with rods, thin-walled tubes, wire rings, and plates either rigidly attached to the converter arm or hanging freely from a hook at the end of the arm. The robustness, large weighing capacity, and accuracy of top-loading balances make them ideally suited for a variety of types of surface and interfacial tension measurements. The converter arm method can be used with a stainless steel rod (3-7 mm in diameter) in vertical-pull surface tension measurements, with samples having volumes of only a few tenths of a milliliter. Measurements on very small liquid volumes are feasible because the rod is firmly attached to the converter arm rather than hanging freely as in measurements with balances mounted above the sample; therefore, the rod cannot swing toward and attach to the wall of small sample tubes. Automation of force and height measurements with the converter arm/top-loading balance method is straightforward. Copyright 1999 Academic Press.

Use of Micellar-Enhanced Ultrafiltration at Low Surfactant Concentrations and with Anionic-Nonionic Surfactant Mixtures

Micellar-enhanced ultrafiltration is a separation technique which can be used to remove metal ions or dissolved organics from water. Metal ions bind to the surface of negatively charged micelles of an anionic surfactant while organic solutes tend to dissolve or solubilized within the micelles. The mixture is then forced through an ultrafiltration membrane with pore sizes small enough to block passage of the micelles and associated metal ions and/or dissolved organics. Monomeric or unassociated surfactant passes through the membrane and does not contribute to the separation. This paper considers advantages of addition of small concentrations of nonionic surfactant to an anionic surfactant; the resulting anionic-nonionic mixed micelles exhibit negative deviation from ideality of mixing which leads to a smaller fraction of the surfactant being present as monomer and a subsequently larger fraction present in the micellar form. The addition of nonionic surfactant improved the separation of divalent zinc substantially at total concentrations above the critical micelle concentration (cmc) of the anionic surfactant. Both zinc and tert-butylphenol (a nonionic organic solute) show unexpected rejection at surfactant concentrations moderately below the cmc, where micelles are absent. This is considered as due to a higher surfactant concentration in the gel layer adjacent to the membrane where micelles are present. Reduction of this rejection at lower transmembrane pressure drops supports this mechanism. Some rejection of zinc was observed in the absence of surfactant but not of tert-butylphenol, indicating an additional effect of membrane charge for ionic solutes. Copyright 1999 Academic Press.

Interfacial behavior of uracil derivatives

The adsorption of a number of methylated uracil derivatives and of 5-fluorouracil has been studied by surface electrochemical methods at a mercury electrode. All derivatives exhibit an initial or dilute adsorption region where they are adsorbed flat on the electrode surface and are bound by pi-electron overlap with the electrode. Uracil, thymine, 1,5-dimethyl-uracil, 5,6-dimethyluracil, 1,5,6-trimethyluracil and 5-fluorouracil undergo a surface reorientation from the initial flat solution activities for each compound. An unsubstituted N(3)-H group is an absolute requirement for a uracil derivative to be capable of adopting the perpendicular surface stance. In the perpendicular orientation the uracil derivative appears to be bound to the electrode primarily via a N(3)-H--(-) electrode bond although a similar but weaker hydrogen bond can be formed via the N(1)-H group for certain compounds.

Temperature dependence of the interfacial behavior of uracil derivatives

The effect of temperature on the interfacial behavior of uracil, thymine and 1,5-dimethyluracil has been used to characterize the thermodynamics of adsorption of these compounds at a mercury electrode-aqueous electrolyte interface. Between 4.5 degrees C and 40 degrees C all three compounds exhibit two adsorption regions. The first, a dilute layer where the molecules adsorb in a flat orientation on the electrode surface. The second, a compact layer where the molecules adsorb in a perpendicular orientation. The thermodynamic constants characterizing formation of these surface layers have been deduced.

Potential and structure controlled interfacial behavior of uracil derivatives

The adsorption and related interfacial behavior of uracil, various methylated uracil derivatives, uridine, uridine-5'-monophosphate and uridine-3'5'-cyclic monophosphate has been studied by surface electrochemical measurements at a mercury electrode. All uracil derivatives exhibit an initial "dilute" adsorption region where the virtually flat uracil residue is absorbed flat on the electrode surface. In the case of uracil and its methylated derivatives the area occupied by one molecule is about 60-70 A2. Uracil, thymine and 1,5-dimethyluracil exhibit a second adsorption region where they rearrange on the surface and adopt a perpendicular orientation and occupy about 40 A2 per molecule. In this perpendicular orientation the uracils are bound to the electrode through the N(3)-H or perhaps N(1)-H functions in a manner similar to their Watson-Crick bonding in nucleic acids. When in the perpendicular orientation the adsorbed molecules undergo extensive stacking (association) interactions, again similar to those observed between adjacent bases in nucleic acids. The ability of a uracil derivative to undergo a surface reorientation is critically dependent on electrode potential, bulk-solution concentration and molecular structure.